论读文件不用fstream的重要性

    FILE *fp=fopen("F:\\QQBrowser_Setup_DNF.exe", "rb");
    fseek(fp, 0, SEEK_END);
    long size = ftell(fp);
    fseek(fp, 0, SEEK_SET);

    vector<unsigned char> vec;
    vec.resize(size);
    fread(&vec[0], sizeof(char), size, fp);
    fclose(fp);
    

49mb文件1s以下，若用fstream耗时1分钟。